Space shuttle science shows how 1908 Tunguska explosion was caused by a comet
June 24, 2009
Trees felled by the Tunguska explosion. Credit: the Leonid Kulik Expedition.
The mysterious 1908 Tunguska explosion that leveled 830 square miles of Siberian forest was almost certainly caused by a comet entering the Earth's atmosphere, says new Cornell University research. The conclusion is supported by an unlikely source: the exhaust plume from the NASA space shuttle launched a century later.
The research, accepted for publication (June 24, 2009) by the journal Geophysical Research Letters, published by the American Geophysical Union, connects the two events by what followed each about a day later: brilliant, night-visible clouds, or noctilucent clouds, that are made up of ice particles and only form at very high altitudes and in extremely cold temperatures.
"It's almost like putting together a 100-year-old murder mystery," said Michael Kelley, the James A. Friend Family Distinguished Professor of Engineering at Cornell who led the research team. "The evidence is pretty strong that the Earth was hit by a comet in 1908." Previous speculation had ranged from comets to meteors.
The researchers contend that the massive amount of water vapor spewed into the atmosphere by the comet's icy nucleus was caught up in swirling eddies with tremendous energy by a process called two-dimensional turbulence, which explains why the noctilucent clouds formed a day later many thousands of miles away.
Noctilucent clouds are the Earth's highest clouds, forming naturally in the mesosphere at about 55 miles over the polar regions during the summer months when the mesosphere is around minus 180 degrees Fahrenheit (minus 117 degrees Celsius).
The space shuttle exhaust plume, the researchers say, resembled the comet's action.
A single space shuttle flight injects 300 metric tons of water vapor into the Earth's thermosphere, and the water particles have been found to travel to the Arctic and Antarctic regions, where they form the clouds after settling into the mesosphere.
Kelley and collaborators saw the noctilucent cloud phenomenon days after the space shuttle Endeavour (STS-118) launched on Aug. 8, 2007. Similar cloud formations had been observed following launches in 1997 and 2003.
Following the 1908 explosion, known as the
Tunguska Event, the night skies shone brightly for several days across Europe, particularly Great Britain -- more than 3,000 miles away.
Kelley said he became intrigued by the historical eyewitness accounts of the aftermath, and concluded that the bright skies must have been the result of noctilucent clouds. The comet would have started to break up at about the same altitude as the release of the exhaust plume from the space shuttle following launch. In both cases, water vapor was injected into the atmosphere.
The scientists have attempted to answer how this water vapor traveled so far without scattering and diffusing, as conventional physics would predict.
"There is a mean transport of this material for tens of thousands of kilometers in a very short time, and there is no model that predicts that," Kelley said. "It's totally new and unexpected physics."
This "new" physics, the researchers contend, is tied up in counter-rotating eddies with extreme energy. Once the water vapor got caught up in these eddies, the water traveled very quickly -- close to 300 feet per second.
Scientists have long tried to study the wind structure in these upper regions of the atmosphere, which is difficult to do by such traditional means as sounding rockets, balloon launches and satellites, explained Charlie Seyler, Cornell professor of electrical engineering and paper co-author.
"Our observations show that current understanding of the mesosphere-lower thermosphere region is quite poor," Seyler said. The thermosphere is the layer of the atmosphere above the mesosphere.
More information: The paper is available at: http://www.agu.org … npress.shtml
-
Space shuttle Columbia's last flight formed clouds over Antarctica
Jul 06, 2005 |
not rated yet |
0
-
Scientist proposes explanation for puzzling property of night-shining clouds at the edge of space
Sep 25, 2008 |
not rated yet |
0
-
AIM to Clear Up Mystery of Elusive Clouds at Edge Of Space
Apr 11, 2007 |
not rated yet |
0
-
NASA satellite reveals unprecedented view of mysterious 'night-shining' clouds
Dec 10, 2007 |
not rated yet |
0
-
Scientists use meteors to investigate climate change and giant waves at the 'edge of space'
May 24, 2005 |
not rated yet |
0
-
Engineers build first sub-10-nm carbon nanotube transistor
Feb 01, 2012 |
4.9 / 5 (29) |
30
-
Something old, something new: Evolution and the structural divergence of duplicate genes
Jan 31, 2012 |
4.6 / 5 (7) |
1
-
The hidden nanoworld of ice crystals: Revealing the dynamic behavior of quasi-liquid layers
Jan 30, 2012 |
5 / 5 (3) |
1
-
Stock market network reveals investor clustering
Jan 27, 2012 |
3.9 / 5 (23) |
8
-
Of microchemistry and molecules: Electronic microfluidic device synthesizes biocompatible probes
Jan 26, 2012 |
5 / 5 (1) |
0
-
Wind Waves in Reservoir ~ Wind run-up and Wind set-up
Feb 08, 2012
-
Balance of oxygen in the atmosphere
Feb 01, 2012
-
The case for a methanol-based economy
Jan 30, 2012
-
Weather in a rotating cylinder
Jan 25, 2012
-
Importance of difference between SVP over ice and water?
Jan 19, 2012
-
Ozone and atmosphere sampling
Jan 16, 2012
- More from Physics Forums - Earth
More news stories
2C warming goal now 'optimistic' - French scientists
French scientists unveiling new estimates for global warming said on Thursday the 2 C (3.6 F) goal enshrined by the United Nations was "the most optimistic" scenario left for greenhouse-gas emissions.
25 minutes ago |
not rated yet |
0
Tidal forces could squeeze out planetary water
Alien planets might experience tidal forces powerful enough to remove all their water, leaving behind hot, dry worlds like Venus, researchers said.
Space & Earth / Space Exploration
3 hours ago |
5 / 5 (1) |
0
|
New views show old NASA Mars landers
(PhysOrg.com) -- The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter recorded a scene on Jan. 29, 2012, that includes the first color image from orbit showing ...
Space & Earth / Space Exploration
5 hours ago |
4.8 / 5 (4) |
2
|
Black holes and star formation
(PhysOrg.com) -- It has long been recognized that galaxy mergers or even close interactions can play a vital role in shaping the morphology of galaxies. One way they can do so, it is thought, is by triggering ...
4 hours ago |
5 / 5 (2) |
1
|
NASA sees Tropical Cyclone Jasmine over Vanuatu and New Caledonia
NASA's Aqua satellite passed over Tropical Cyclone Jasmine on Feb. 8, 2012 as it was passing between Vanuatu and New Caledonia. NASA imagery showed Jasmine had a 20 nautical mile-wide eye.
Space & Earth / Earth Sciences
3 hours ago |
not rated yet |
0
Secrets of immune response illuminated in new study
When disease-causing invaders like bacteria infect a human host, cells of various types swing into action, coordinating their activities to address the threat.
Nanotube therapy takes aim at breast cancer stem cells
Wake Forest Baptist Medical Center researchers have again proven that injecting multiwalled carbon nanotubes (MWCNTs) into tumors and heating them with a quick, 30-second laser treatment can kill them.
Potentially important new mechanisms found anti-aging effects of resveratrol
A well-conducted experimental study in mice has provided potentially important new insights into the association of the intake of resveratrol and like compounds with health benefits. Resveratrol is a constituent of red wine ...
Touch screens create online shopping experiences at stores
Imagine browsing knife sets in an airport and then ordering one before you board your plane, or going to a department store to look at makeup without having to bounce from counter to counter to check out each brand's selection.
Doctors telling more adults: Get out and exercise
(AP) -- More and more U.S. adults are being told by their doctor to get out and exercise, according to government survey released Thursday.
Study shows fainting factor in cardiac arrests
A new study by Dr. Andrew Krahn shows that over a quarter of unexplained cardiac arrests occurred after the patient had an event of fainting, known as syncope. According to Dr. Krahn, a Cardiologist at London Health Sciences ...
Jun 24, 2009
Rank: 1.5 / 5 (2)
Jun 24, 2009
Rank: 1 / 5 (1)
Jun 24, 2009
Rank: 1 / 5 (2)
I think I may have heard something once about a theoretical weapon that would basically drop very large rods of metal from a "weaponized" satellite, to try and achieve something like this.
Jun 24, 2009
Rank: 4.3 / 5 (4)
Details
=======
The energy released from the impact of a comet is 1/2mv^2 (half m v squared). The relative velocity of the comet to the earth is very high. Then you square it and you get a big number. Then multiply it by its mass (in kg) and you quickly get energy of a magnitude comparible to kilo tons of TNT explosives i.e. small nuke.
Math
====
Velocity of comet approx. =100,000 km/hr =28,000 m/s
(based on halleys comet)
Mass approx. = 10^14 kg
(based on Comet 9P/Tempel 1 aka "deep impact")
Energy = (28 x 10^17)^2 Joules
1 Megaton of TNT = 4 x 10^15 J
Energy = (700)^2 MegaTons TNT.
Biggest nuke tested (Tsar Bomb) approx = 100 megaton
Jun 24, 2009
Rank: 1 / 5 (1)
Jun 24, 2009
Rank: 1 / 5 (2)
Jun 24, 2009
Rank: 2 / 5 (1)
i think a good analogy would be jumping out of a plane at 10,000 ft without a parachute into a lake. water flows around you when you swim right, yet its as hard as concrete when you hit it at terminal velocity.
in other words, even a liquid ball of water hurling into our atmosphere would likely have a similar effect.
defunct-yes at one point there was a proposal for a satellite weapon to launch rockets or even simple metal rods from space. however, its against international treaty and always will be until the "Federation" becomes reality on our planet :)
Jun 25, 2009
Rank: 1 / 5 (1)
comments travel at some speed. This is tremendous amount of energy, and it has to be released upon entry/collision.
kinetic-energy weapons, rods from gods :http://www.popsci...rods-god
Jun 25, 2009
Rank: 1 / 5 (1)
I'm with you guys on this one. These researchers are just saying they made a connection with some clouds.. that is all. They probably didn't even run any simulations to see if it could possible be a comet and what the size of it would need to be to devastate such a large area. In the end, the only thing to be gleamed from this article is that the researches believe there was a large amount of water involved in the event, that is all.
Jun 25, 2009
Rank: 1 / 5 (1)
Ricochet writes:
The energy released from the impact of a comet is 1/2mv^2 (half m v squared). The relative velocity of the comet to the earth is very high. Then you square it and you get a big number. Then multiply it by its mass (in kg) and you quickly get energy of a magnitude comparible to kilo tons of TNT explosives i.e. small nuke.
This does not even come into play because the solid object (comet) never impacted the terrestrial surface but rather exploded some distance above it's likely landing spot if it were an asteroid. We know this because the Russian study provided evidence that with intense damage to the landscape, but no crater was found. So what caused the multi megatonne explosion? Embedded in the ice crystals and in the crystalline silicate gains the comet contained highly explosive volatile gases such as methane which ignited under the intense pressure from atmospheric entry. All of the gas gas bubble ignited almost simultaneously in a chain reaction causing a massive explosion; displacement of huge volumes of air and micro crystalline cometary particles which felled the forest.
You can see what crystalline cometary grains look like at this link.
http://www.bccmet...ge4.html
Stellar grains here.
http://www.bccmet...ge3.html
Jun 25, 2009
Rank: 1 / 5 (2)
I suppose you believe that getting hit by a frozen turkey does more damage than getting hit by a thawed one.
Jun 26, 2009
Rank: not rated yet
Actually, that was Googleplex that wrote that...
Jun 27, 2009
Rank: not rated yet
Jun 28, 2009
Rank: 1 / 5 (1)
Jun 28, 2009
Rank: not rated yet
Just guessing, but I would think that observers then would find even a small increase in "brightness" significant - much less, perhaps, than we can see nowadays without instrumentation.